 During most of this time he was also Chief Scientific Advisor to the Intelligence Services and national Co-ordinator Intelligence R&D.At GCHQ, Benjamin played an important role in the original development of "non-secret cryptography", later independently discovered by Rivest, Shamir, and Adleman and termed public-key cryptography.As a visiting Professor at the University of Surrey between 1972 and 78 he helped to start the Surrey University mini-satellite programme.